A century-old mystery in female anatomy is being rewritten by new scientific findings: the rete ovarii, long dismissed as a vestigial and “useless” organ, may play a critical role in ovarian function and fertility. This revelation comes from a pioneering mouse study published in March 2025 in the journal eLife, which suggests that this overlooked structure is not only active but potentially essential for reproductive health (Live Science).
The discovery is especially significant for Thai readers, where women’s health issues, particularly regarding fertility and reproductive well-being, remain top concerns for many families and the medical community. For generations, biology textbooks and medical curricula worldwide—including those in Thailand—have listed the ovaries, uterus, and fallopian tubes as the primary organs of the female reproductive tract. The new research now puts the rete ovarii (RO) on the map, suggesting it should be investigated as an additional component crucial to female reproductive function.
First identified in humans in 1870, the RO is a horseshoe-shaped network of tubes that nestles beneath the ovary, where blood vessels and nerves enter the organ. For more than a century, its purpose was unclear; lacking the ability to observe its activity, early scientists concluded the RO served no purpose—a so-called evolutionary leftover. According to Professor Adam Taylor, an anatomist at Lancaster University, this misunderstanding was a direct result of technological limitations at the time. “When this structure was first discovered in the late 1800s, it was assumed that it had no purpose because scientists couldn’t see its function within the body,” Taylor noted, highlighting the advances made possible by today’s imaging and molecular techniques.
The new study leveraged these modern tools, including mass spectrometry and fluorescent dye tracking, to study living mice as well as tissue samples. Researchers found the RO contains three distinct, functionally specialized regions: the intraovarian rete (IOR) within the ovary, the extraovarian rete (EOR) consisting of convoluted tubules, and the connecting rete (CR) bridging the two. Intriguingly, these three regions mature during fetal development and persist into adulthood, upending the idea that the RO is simply a fetal relic.
Mass spectrometry revealed thousands of proteins being produced within the EOR at birth, among them the insulin-like growth factor-binding protein 2 (IGFBP2). This protein can modulate the activity of insulin-like growth factors—compounds crucial for the development and maintenance of ovarian follicles carrying immature eggs. In another experiment, fluorescent dye tracked fluid movement within the EOR, indicating that the RO may actively move proteins and signals toward the ovary.
The study also showed that cells within the RO express genes for various hormone receptors, such as those for estrogen and progesterone—the key hormones governing the menstrual cycle and overall female reproductive health. This suggests a dynamic, hormone-sensing and possibly hormone-modulating role for the RO, making it far from a mere bystander.
Professor Taylor, who was not part of the study, summarized the implications: “It appears that the rete ovarii may have a role in ovarian homeostasis—maintaining the ovaries and their environment. Similarly, they appear to be able to detect fluid movement in and around the ovaries and their microenvironment. Finally and most interestingly is the potential endocrine [hormonal] role that the rete ovarii may have.” The researchers went further, raising the idea that the EOR might act “as an antenna”—receiving hormone and nerve signals from across the body and relaying them to the ovary via secreted proteins.
The researchers behind the study, led by Dr. Dilara Anbarci, a developmental biologist at the University of Michigan, now plan to see how the EOR responds to hormonal cues and whether the proteins it produces change in response to bodily changes. “There’s still so much we can’t even begin to comprehend about female anatomy,” Dr. Anbarci told Science News. “I hope this encourages more investigation in reevaluating what we don’t already know about the ovary.”
Why does this matter for Thailand? The answer lies in two areas. First, Thailand, like much of Southeast Asia, is seeing rising rates of infertility and ongoing public health debates regarding reproductive health education, medical access, and societal expectations for women (Bangkok Post, WHO Thailand Fertility Data). Understanding each component of the reproductive tract—including those once dismissed—opens new doors for diagnosing, treating, or even preventing conditions like polycystic ovary syndrome (PCOS), premature ovarian insufficiency, and endometriosis, all of which impact Thai women in significant numbers.
Second, Thai medical education and research have long mirrored Western textbooks, sometimes overlooking discoveries relevant to Asian populations. With this breakthrough, there’s a fresh opportunity for local universities and hospitals such as Siriraj and King Chulalongkorn Memorial Hospital to study the role of the RO in Thai women, possibly adapting guidelines or diagnostic techniques with greater regional relevance. This could also foster closer collaboration between Thai and global scientists on reproductive biology research.
Some Thai experts are already calling for a reconsideration of what is “known” about the female body. Dr. Supaporn Charungchit, a reproductive endocrinologist in Bangkok (not involved with the study), commented in a recent interview: “Too often, so-called ‘minor’ organs are ignored until a disease appears. These fresh findings remind us to remain humble and curious, as the body’s complexity is still largely a mystery.”
Culturally, Thai society places great value on family and motherhood, but there remains a notable lack of public dialogue about gynecological health. This new research might serve as a springboard for better reproductive education, encouraging women—and the men in their lives—to seek more nuanced information about fertility, menstruation, and hormonal wellness. In rural areas, where cultural beliefs occasionally influence health-seeking behavior, myth-busting scientific discoveries like this are especially important.
Historically, many body parts have been misunderstood, sometimes classified as vestigial before being re-appreciated. The appendix, for instance, was long thought to be useless until modern research revealed its immune functions. Similarly, the tonsils and even “junk DNA” have proven their worth over time. The story of the RO fits this pattern: scientific humility in the face of the body’s enduring mysteries.
Looking ahead, further research may produce tests or treatments based on RO function, create new fertility interventions, or improve ovarian disease prevention. The authors of the study emphasize that deeper insight into all structures of the female reproductive tract can “open up therapeutic avenues and opportunities in treating various conditions.” For Thailand, this might mean improved screening for fertility issues, better hormone therapies, and a richer dialogue around the biology of being female—finally moving away from hōhāk (โหหัก—futile, useless) to hữu ích (มีประโยชน์—beneficial and essential).
For Thai readers, the takeaway is clear: embrace new knowledge, support research initiatives on women’s health, and ask your doctor about medical advances that redraw what’s possible in female reproductive medicine. Advocating for greater inclusion of such findings in school health curriculums and women’s wellness programs will ensure that Thailand is at the forefront of benefiting from these global breakthroughs. As with all medical updates, consult with your healthcare provider for the most up-to-date advice relating to your personal health situation.
For those interested in further reading, the original study is detailed in eLife (doi: 10.7554/eLife.93015, eLife journal), with additional coverage at Live Science. This developing story is a reminder that the journey to health is an ongoing one, driven by curiosity, science, and respect for every organ in the human body.